In the Garden:
Sometimes you can't wait to find out what's wrong with your tree. This one needed to come down.
What Went Wrong?
Suppose you walk out into the garden one day and notice that one of the trees looks pale or even wilted. Or there's a bunch of gray, lacy-looking stuff on the branches, or a pile of sawdust on the ground by the trunk, or all the leaves on one branch have turned brown, apparently overnight. Maybe what was a nick in the trunk is now oozing something yucky. Ignoring these relatively early signs of trouble can be fatal to the tree. You can spend a lot of time researching the exact problem to diagnose the organism that caused it and look for a specific response. But, fortunately for gardeners, that's not necessary because tree troubles fall into general categories that determine how you should respond.
Problems and Fixes
Pale green leaves and wilting branches most obviously signal drought stress, but if it's been very rainy, or if the tree is young, think again. Root problems that aren't allowing fertilizer and water to reach the canopy also can cause this response. Replant if practical, or prune the tips to reduce stress and apply a fungicide drench.
Lichen -- grey growth on tree branches -- is not a problem in itself, but an indicator of branches that need to be pruned out. Follow the pruning with fertilizer to stimulate new growth.
If a pile of sawdust is below neat holes in the trunk, you have a boring insect and need to spray a general purpose insecticide immediately. Coat the trunk and fill the hole with pesticide.
Sometimes a branch just dies, so you prune it out and the tree is fine. Unfortunately, at times the first branch is the start of dieback that's eventually fatal. Be sure to cut the bad branch off completely and cut back at least a few inches into the good wood. If the tree is a pear or a relative like pyracantha, the problem may be fireblight. Prune completely out, then plan to spray as the new growth starts with streptomycin. It may not work, but it's worth a try.
Icky oozes where wounds have healed (or tried to) usually means a secondary organism (frequently a bacteria) has invaded. Clean the wound, keep the area dry, and unless the damaged tree creates an immediate hazard, continue its routine care of water and fertilizer.
Resources for Gardeners
Online, in the library, and at the Extension Service, there are plenty of ways to find out what the trouble is and exactly what to do about it. I answer questions weekly at http://www.gardenmama.com and would be happy to help you there.
Obviously, if a sick tree threatens to fall on people or houses, it must be removed. Consult a professional arborist for such work; be sure whomever you hire is licensed and bonded and check their references with a few phone calls. But if there's no threat, and you can stand to look at it, prune the tree severely to rejuvenate it. Often the tree's roots are alive and it will continue to grow, but even if it's not, you can use the trunk to grow vines on and as a home for wildlife.
Care to share your gardening thoughts, insights, triumphs, or disappointments with your fellow gardening enthusiasts? Join the lively discussions on our FaceBook page and receive free daily tips!